I stilll think that saying "That's a good question" is just about the stupidest thing anybody can say.
Everytime somebody said that to me, I always wanted to say right back:
"I know it's a good question, that's why I asked it. Do you have a good answer for it?"
"I have a simple question is worse"! I hate when forum members add that to the post. First off it is superfluous. But what is worse os how do you know that a question is simple if you don't know the answer?
I have seen a great many posts where the OP wrote "simple question" and the thread went on for multiple pages.